Method for mitigating the effects of coil collapse on hot strip mill coils

A method for mitigating the effects of coil collapse on hot strip mill coils without insertion of a mechanical means into the coil eye to limit sagging, the method comprising the steps of:

• producing a hot rolled steel sheet in a hot strip mill;
• forming a hot strip coil by coiling the hot rolled steel sheet around a mandrel on a downcoiler;
• orienting the hot strip coil such that the coil eye axis of the hot strip coil is in a horizontal direction;
• removing the hot strip coil from the mandrel/downcoiler;
• pre-sagging the hot strip coil to create an initial sag by allowing gravity to cause the coil to sag in a first specific direction for a first period of time, thereby causing the coil to become pre-sagged;
• without inserting a mechanical means into the coil eye to limit sagging, modifying a direction of the sag caused by the force of gravity to a direction perpendicular to the first specific direction and allowing gravity to sag the coil in the modified direction for a second period of time;
• wherein the hot strip coil being cooled enough by the end of the second period of time such that the rate of sagging of the hot strip coil has become negligible;
• wherein the step of pre-sagging said hot strip coil includes the steps of:
• placing the hot strip coil onto a support positioned within the coil eye, the coil hanging by the coil eye from the support;
• hanging the hot strip coil, without rotation about said coil eye axis, for the first period of time, wherein said first period of time is between 1 and 6 minutes;
• the pre-sagging creating a maximum coil eye diameter (Dmax) dimension between a top and a bottom of the hot strip coil in the direction parallel to the force of gravity.